Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 38: Focus: Rheology II (joint focus with DRG)
CPP 38.9: Vortrag
Freitag, 30. März 2012, 11:45–12:00, C 130
Influence of carbon dioxide on the viscoelastic properties of polystyrene melts — •Ulrich A. Handge1,2 and Volker Altstädt1 — 1Department of Polymer Engineering, Faculty of Engineering Science, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth — 2Helmholtz-Zentrum Geesthacht, Institute of Polymer Research, Max-Planck-Strasse 1, 21502 Geesthacht
The addition of carbon dioxide to polystyrene strongly influences the viscoelastic properties of polystyrene. Carbon dioxide is dissolved in the polymer matrix and acts as a plasticizer. Generally, the glass transition temperature and the viscosity of polystyrene/carbon dioxide solutions decrease with increasing carbon dioxide concentration. In this work, the linear viscoelastic properties of solutions of polystyrene melts with carbon dioxide are investigated. A rotational rheometer which is equipped with a pressure cell allows one to perform experiments using a plate-plate rheometry. The pressure cell can be filled with the blowing agent carbon dioxide, and torque and normal force are transferred via a magnetic coupling to the measurement head of the rheometer. We study the transient shear rheology and test superposition principles of the rheological properties with respect to time, temperature, pressure and concentration of the blowing agent. These measurements allow us to analyze the linear viscoelastic properties of polystyrene/carbon dioxide solutions, in particular the influence of carbon dioxide on the average relaxation time of polystyrene. Our data indicate that glass transition temperature and average relaxation time of polystyrene are strongly influenced by the addition of carbon dioxide.